Magnesium chelatase

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magnesium chelatase
Identifiers
EC number 6.6.1.1
CAS number 9074-88-8
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / EGO
Magnesium chelatase, ChlI subunit
Identifiers
Symbol Mg_chelatse_chII
Pfam PF01078
InterPro IPR000523
CobN/magnesium chelatase
Identifiers
Symbol CobN/Mg_chltase
Pfam PF02514
InterPro IPR003672

Magnesium-chelatase is a three-component enzyme that catalyses the insertion of Mg2+ into protoporphyrin IX. This is the first unique step in the synthesis of bacteriochlorophyll. As a result, it is thought that Mg-chelatase has an important role in channeling intermediates into the (bacterio)chlorophyll branch in response to conditions suitable for photosynthetic growth:

Magnesium chelatase.svg

protoporphyrin IX + Mg2+
+ ATP + H
2
O
\rightleftharpoons ADP + phosphate + Mg-protoporphyrin IX + 2 H+

The 4 substrates of this enzyme are ATP, protoporphyrin IX, Mg2+, and H2O, whereas its 4 products are ADP, phosphate, Mg-protoporphyrin IX, and H+.

This enzyme belongs to the family of ligases, specifically those forming nitrogen-D-metal bonds in coordination complexes. The systematic name of this enzyme class is Mg-protoporphyrin IX magnesium-lyase. Other names in common use include protoporphyrin IX magnesium-chelatase, protoporphyrin IX Mg-chelatase, magnesium-protoporphyrin IX chelatase, magnesium-protoporphyrin chelatase, magnesium-chelatase, Mg-chelatase, and Mg-protoporphyrin IX magnesio-lyase. This enzyme participates in porphyrin and chlorophyll metabolism.

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